A known electrophotographic image forming apparatus includes a main body and an image carrier disposed in the main body and configured to carry a developer image thereon.
The image forming apparatus includes a main body, and a process cartridge including a photosensitive drum. The process cartridge is configured to be mounted onto and removed from the main body. The process cartridge includes a coupling device. The main body includes a main body coupling device configured to engage the coupling device of the process cartridge.
In the image forming apparatus, the main body coupling device includes a coupling recessed shaft configured to engage the coupling device of the process cartridge, and a large gear integrally formed with the coupling recessed shaft. Drive force from a motor is configured to be input to the large gear and transmitted to the coupling device of the process cartridge, via the coupling recessed shaft.